<p>Disclosed are a therapeutic agent and a prophylactic agent for gastrointestinal diseases. A peptide comprising an amino acid sequence represented by the formula Ser-Ser-Ser-Arg or a pharmaceutically acceptable salt thereof can promote the wound healing in a gastrointestinal mucosal tissue, and is therefore useful as a therapeutic agent or a prophylactic agent for gastrointestinal diseases. When a combination of (a) a peptide comprising an amino acid sequence represented by the formula Ser-Ser-Ser-Arg or a pharmaceutically acceptable salt thereof and (b) a peptide comprising an amino acid sequence represented by the formula Phe-Gly-Leu-Met-NH2 or a pharmaceutically acceptable salt thereof is administered, these components act synergistically to significantly promote the wound healing in a gastrointestinal mucosal tissue.</p>
